The present invention relates to carburetors and throttle bodies as used in internal combustion engines. More particularly, the present invention relates to throttle bodies that are adapted to pass air to a manifold associated with the engine. Additionally, the present invention relates to modifications of the air passageways found in the throttle body so as to obtain greater volumetric efficiency at low r.p.m.""s, for the engine, compared to current standard designs.
Conventional throttle bodies are mounted within the air intake stream of an internal combustion engine. Typically, a butterfly valve is employed to control the amount of air flow through the throttle body and consequently, the entire r.p.m. speed. The butterfly valve is mounted on a throttle shaft, which is, in turn, coupled to the vehicle accelerator pedal and possibly other actuating mechanisms.
Present internal combustion engines that utilize liquid fuel will typically utilize a throttle mechanism which is formed of an external block containing one or more cylindrical passageways.
These passageways are subjected to a constrictive flow by a thin cylindrical solid disk contained within the cylindrical passageway. The disk is on a centrally located axle located at the mid-point of and center-line transverse to the passageway. The rotation of the axle/disk assemblage causes the passageways to be variably closed or opened in unison. Under normal operating conditions, aspirated air is allowed to flow through these passageways and introduced into the cylinders of the engine. The flow of aspirated air can be controlled by the rotation of the disk contained within the passageway. The amount of this aspirated air, relative to the subsequent injection of liquid fuel, determines what is normally termed volumetric efficiency. This capacity to fill a cylinder or cylinders, to the greatest amount possible with the optimum fuel/air mixture, determines the force engendered on the piston or pistons upon ignition of this mixture. Typically, at slow speeds or low r.p.m.""s, the volumetric efficiency of an engine is lower than that achieved at higher speeds. This occurs principally because of the high constriction of air flow due to the position of the disk in the air flow passageway of the throttle body mechanism. The rotation and position of the disk does not result in a linear increase in the area exposed to air flow. For example, ten degrees of rotation of the disk does not result in double the air flow as a rotation of only five degrees. When the disks are fully closed in the throttle body, it is considered to be in an xe2x80x9cidlexe2x80x9d position with aspirated air flow at a bare minimum. At opening, in present throttle bodies, the amount of aspirated air is very slowly increased. As opening continues, the amount of aspirated air is dramatically increased and, as a result, volumetric efficiency increases.
FIG. 1 illustrates a conventional throttle body 10 as used on an internal combustion engine. The throttle body assembly 10 includes a throttle body housing 12 which assembles into an air intake system for an internal combustion engine, not shown. The throttle body housing 12 includes air flow bores 14 and 16 through which intake air is directed during operation of the internal combustion engine. The output of the throttle body assembly 10 will direct air to the manifold of the internal combustion engine. From the manifold, air can be directed into the engine cylinders for mixture with the fuel.
In FIG. 2, it can be seen that the air flow bores 14 and 16 are closed by the use of disks 18 and 20, respectively. Disks 18 and 20 are affixed centrally to an axle 22 extending transversely across the longitudinal axis of the air flow bores 14 and 16. The rotation of the axle 22 will cause a corresponding rotation of each of the disks 18 and 20 so as to allow air flow through the bores 14 and 16, respectively.
In FIG. 3, there is shown a cross-sectional view of the air flow bore 14. It can be seen that the disk 18 is shown in a first position in which the outer periphery of the disk 18 rests against a seat 24 formed on the interior wall 26 of the throttle body 12. When the disk 18 has its periphery against the seat 24, the air flow bore 14 is closed so as to prevent air from passing therethrough. When the accelerator of the vehicle is pressed downwardly, the disk 18 will pivot about axle 22 so as to allow air flow to pass in the area beyond the periphery 28 of disk 18 and the wall 26 of the throttle body 12. The amount of rotation of the disk 18 will determine the amount of air that is possible to flow in the spaces between the periphery 28 of the disk 18 and the wall 26 of the throttle body 12.
In FIG. 3, it can be seen that the air flow bore 14 has a first section 30 and a second section 32 arranged on opposite sides of the disk 18. The wall 26 in section 30 is of substantially straight and even diameter extending to the seat 24. Similarly, the wall 34 in the second section 32 is substantially straight and uniform and extends from the seat 24.
In normal use, a volumetrically inefficient amount of air will flow past the disk when the disk 18 is rotated only with small angular deflection. As such, the engine will receive a volumetrically inefficient amount of air. Ultimately, when the disk 18 has rotated fully, the engine will run at an optimum volumetric efficiency at a predetermined operational speed.
Several problems have been associated with attempts to increase the diameter of the air flow bore 14 in the second section 32. Initially, the restrictions caused by the casting of the throttle body 12 will prevent any undue expansion of such air passageway. The relatively small diameter of the air flow bore 14 serves to create better transitions for the power train of the vehicle. Additionally, an increase in the diameter of the bore associated with the air flow passage is believed to create non-laminar flow and thus create an inefficiency in the delivery of air to the manifold.
In the past, various patents have issued relating to the delivery of air to the cylinders of a vehicle. In particular, U.S. Pat. No. 3,721,431, issued on Mar. 20, 1973 to P. Landrum, describes a fuel preparation system for a carburetor which utilizes an air supply conduit of predetermined dimensions communicating with each idle port of the carburetor with means for heating air passing through a conduit at predetermined temperature. Lateral openings in air supply conduits adjacent to the idle port receive fuel from the fuel supply passageway to supply heated mixture of fuel and air to the idle port.
U.S. Pat. No. 4,078,025, issued on Mar. 7, 1978 to T. Kato teaches a carburetor having an air port provided adjacent a slow port so as to supply air from the air port when fuel is supplied from the slow port in a slow speed operation of the engine. The air port is biased with respect to the slow port so that the supply of air from the air port is more rapidly reduced than the supply of fuel from the slow port in the transition region from a slow speed operation to the normal operating condition. This will compensate for a delay in the fuel supply from a main nozzle in the transition region.
U.S. Pat. No. 4,305,892, issued on Dec. 15, 1981 to I. H. Hallberg, describes a carburetor in which fuel is supplied to a pair of tubular members. These tubular members may be of equal or different diameters and are disposed across a housing opening through which air flows. The velocity of such air is controlled by a throttle valve or by a damper means. Each tubular member is constructed with a generally upwardly directed slot or fuel gap such that the air strips fuel therefrom. The throttle valve or damper may be of the iris type or of a type having a pair of vanes pivoted outwardly of the center thereof so as to initially open at the center thereof. At small throttle openings, air flowing to the engine is concentrated over the fuel gap of the lower member. This results in high air velocities at low air flow rates.
U.S. Pat. No. 4,329,964, issued on May 18, 1982 to G. Q. Morris, describes a carburetion system for metering liquid fuel for supply to an internal combustion engine. Metered liquid fuel is delivered through one branch of the metering system to the engine intake air downstream of the throttle at small and medium engine loads. The liquid fuel is delivered through the other branch to the engine intake air upstream of the throttle at large engine loads. The fuel flow is transitioned between the branches in an automatic manner and occurs in response to pressure differentials within the system. Fuel delivered to the engine intake air downstream of the throttle valve may be heated or otherwise treated to improve liquid fuel atomization or vaporization.
U.S. Pat. No. 4,379,096, issued on Apr. 5, 1983 to Yokoyama et al., describes a carburetor in which an air/fuel mixture is fed to each cylinder so as to maintain a uniform air/fuel ratio in the course of transit from the primary side to the secondary side of the carburetor. An independent secondary slow-running fuel system is provided for each cylinder and a secondary slow mixture path includes a pipe connected between a carburetor and a manifold.
U.S. Pat. No. 4,387,063, issued on Jun. 7, 1983 to Pontoppidan, et al. describes a carburetor having a main fuel supply system for normal running, which opens into a venturi in the induction passage of the carburetor. There is at least one auxiliary circuit for supplying a flow of air/fuel mixture for low speed and low-load operation of the engine. The mixture control for the circuits are carried by a distribution block arranged to be inserted and removably fixed in the part of the induction passage situated in the vicinity of a venturi.
U.S. Pat. No. 4,539,163, issued on Sep. 3, 1985 to Sakurai, et al. teaches a carburetor which includes an enrichment circuit having a port in the induction passage upstream of the idle position of the throttle valve and which is served by a fuel well. The discharge of the enrichment circuit is controlled by a throttle valve position responsive valve.
U.S. Pat. No. 4,966,735, issued on Oct. 30, 1990 to M. LoRusso, describes a non-leaking venturi carburetor which has a generally cylindrical bore into which are fitted removable liners. The inner liner surfaces are contoured as a venturi wherein a circular inlet section narrows down to a throat after which the outlet section generally expands in flow area. The fuel discharges into the venturi through a plurality of ports in the venturi wall. These ports are located around the periphery of the venturi and generally in the vicinity of the venturi throat.
It is an object of the present invention to provide a throttle apparatus which greatly improves the volumetric efficiency and thus, torque, of the engine at low speeds.
It is another object of the present invention to provide a throttle apparatus which boosts acceleration due to greater torque at low speeds.
It is a further object of the present invention to provide a throttle apparatus which greatly improves fuel economy.
It is another object of the present invention to provide a throttle apparatus which reduces the emission of hydrocarbons and other pollutants.
It is still another object of the present invention to provide a throttle apparatus which is easy to manufacture, easy to use and relatively inexpensive.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is a throttle apparatus that comprises a throttle body having an air passageway extending therethrough, an axle rotatably mounted in the throttle body and adapted to rotate in relation to a movement of the accelerator pedal, a disk affixed to the axle so as to pivot relative to the rotation of the axle, and a channel formed in a wall of the throttle body in one side of the disk. The disk is movable between a first position adapted to block the air flow through the passageway and a variable second position adapted to allow air flow through the passageway. The channel is formed in the wall of the throttle body so as to have an end separate from and adjacent to the disk when the disk is in the first position.
In the present invention, a seat is formed in the passageway of the throttle body. The seat extends radially inwardly from the wall. The seat extends circumferentially around the disk in the first position. The disk has a circular configuration and the seat has an annular configuration. The disk is in generally sealing contact with the seat in the first position. The channel has an end immediately extending from the seat.
The disk defines a first section and a second section of the air passageway when the disk is in the first position. The first section is adapted to receive the air flow prior to passing by the disk into the second section. The channel is preferably formed in the second section. In the preferred embodiment of the present invention, the channel comprises a plurality of channels extending longitudinally along the second section. The plurality of channels have a bottom extending into the wall. The second section has a greater cross-sectional area than the cross-sectional area of the first section. The plurality of channels are arranged in generally spaced parallel relationship to each other. In the preferred embodiment of the present invention, each of the plurality of channels has a similar cross-section. Also, the plurality of channels may be arranged halfway around or entirely around the air passageway of the second section.
In an alternative form of the present invention, the plurality of channels extend longitudinally along the first section so as to have an end adjacent to and separate from the disk when the disk is in the first position. In another alternative form of the present invention, the channels in the wall of the second section extend in a generally helical (or rifled) configuration.
The disk is angularly displaceable about the axle so as to allow a controlled amount of air flow through the space between a periphery of the disk and the wall of the air passageway. The arrangement of channels have a depth and size adapted to obtain a desired volumetric efficiency of an engine through which the air flow passes. The channels are configured to be parallel to a path of air flow past the disk.